New Zealand's intelligence agency, the Government Communications Security Bureau (GCSB), has taken what it calls a "very unusual step" in making a public comment on the case of the Waihopai spybase saboteurs.

The base, in Marlborough's Waihopai Valley, was not "a United States spybase in our midst, contributing to torture, war, and the use of weapons of mass destruction and other unspeakable evil," director Sir Bruce Ferguson and his predecessor Warren Tucker, said in a statement today.

A jury last month found teacher Adrian Leason, 45, Dominican friar Peter Murnane, 69, and farmer Sam Land, 26, not guilty of charges of burglary and wilful damage after they broke into the spybase in 2008 and deflated one of the radar dome covers.

Solicitor-General David Collins yesterday ruled out appealing their acquittal but he may try to sue them for $1.1 million for the damage done to Government property.

But the GCSB directors said assertions made in the media "demand a response in the wider public interest, because they bring into question the core integrity of New Zealand's security and intelligence apparatus".

"The claims that the Waihopai station is 'a United States spybase in our midst', contributing to 'torture, war, and the use of weapons of mass destruction' and other 'unspeakable evil' cannot be left unchallenged", they said.

More fundamental were the issues of the propriety and legality of the actions of the GCSB throughout the period leading up to, during, and since the US-led invasion of Iraq, they said.

It was a fundamental question of New Zealand's sovereign control over its decision-making on matters of foreign policy.

That was closely linked to the way New Zealand's instruments of national influence, such as intelligence agencies, assisted and supported Government decisions.

"Consistent with the clearly-expressed and very public position taken by the then Government on the Iraq War, very specific and explicit steps were taken throughout the GCSB to ensure that nothing was done (or tolerated) which could in any way be construed as being in conflict with the New Zealand Government's position on the Iraq war. This includes the uses to which the Waihopai station was tasked.

"The Waihopai station is not a US-run 'spybase'. It is totally operated and controlled by New Zealand, through the GCSB as an arm of the New Zealand Government."

Allegations had been investigated and reported upon in the 1990s by the Inspector-General of Intelligence and Security, at the request of Prime Minister Bolger, in response to claims made by peace movement activists.

Waihopai was not being used to contribute to torture, war, and the use of weapons of mass destruction, such as depleted uranium as claimed, the directors said.

"It was not - and is not - contributing to 'unspeakable evil'. Quite the reverse."